Nonlinear dynamic response and stability analysis of the stapes reconstruction in human middle ear

Stapes fracture causes hearing loss and instability in the middle ear hearing system(MEHS). The material used in the stapes reconstruction restores stapes, but the effects of the nonlinear material parameters on the stability of the MEHS are still unknown. To address this challenge, the nonlinear dynamic response and stability of the stapes reconstruction are investigated using a multi-degree-of-freedom mechanical model. The material parameters of the implant are tentatively determined by analyzing the natural frequencies of the undamped system. The dynamical properties of the MEHS are characterized under different external excitations. The approximate solution of the MEHS near the resonant frequency is derived through the multiple-time-scale method(MTSM). The results show that the nonlinear stiffness of the material has little influence on the MEHS in the healthy state, but it causes resonant phenomena between the ossicle and the implant in the pathological state.

Expression of TAC1 and Its Receptors TACR1,TACR2,TACR3 Genes in Different Goat Tissues Under Different Photoperiods

This study was conducted to analyze the regulation mechanisms of TAC1,TACR1,TACR2 and TACR3 genes on reproduction of goat under different photoperiods. The expression conditions of TAC1,TACR1,TACR2 and TACR3 genes in 12 tissues( oviduct,ovary,uterus,gluteus,mesenteric fat,brain,cerebellum,medulla oblongata,hart,lung,liver,kidney) of adult Henan Huai goat under different photoperiods( short day light,Light 8 h∶ dark 16 h,and long day light,light 16 h∶ dark 8 h) were analyzed by q-PCR method. TAC1,TACR1,TACR2 and TACR3 genes were expressed in all the 12 tissues of goats,with different expression characteristics; and the expression levels of all the genes were affected by photoperiod and changing of light signal between light and dark under short photoperiod. Shifting of light signal from dark to light was more conductive to the expression of these genes in all tissues than that of light signal from light to dark.There were significant differences in the expression levels of genes between light shifting from light to dark and from dark to light when the genes were expressed at a higher level in some tissues. TAC1 and TACR2 genes were expressed at a higher level than TACR1 and TACR3 genes in the various tissues,which implied that TACR2 is a receptor given priority to combine with TAC1 when TAC1 is functional.

Assessment of Serum PRL,MLT,TSH,FSH and LH Concentrations in the Goat (Capra hircus) Exposing to Different Photoperiod Regimes

In many seasonally breeding species,photoperiod is an important factor involved in reproduction. Capra hircus breeds are normally considered short-day breeders. An experiment was carried out to evaluate whether or not photoperiodic regimens influence circulating hormone levels( prolactin,melatonin,thyrotropin stimulating hormine,luteinizing hormone,follicle stimulating hormone) of Henan huai local goat exposing to different photoperiodic regimens. The results showed that plasma levels of prolactin,melatonin,thyrotropin stimulating hormine,luteinizing hormone and follicle stimulating hormone were higher in the 8 L∶ 16 D photoperiodic regimen than that in the 16 L∶ 8 D photoperiodic regimen. Levels of those hormones decreased on day 7 and day 28 when the 16 L∶ 8 D photoperiodic regimen was used continuously. It was concluded that serum concentrations of the hormones increased in summer when short day( 8 L∶ 16 D) was used and decreased when the goats were transferred from short day for 42 d to long day exposure for 28 d. We suggest that in summer,levels of hormones changing may be due to short day animals. Changing of related hormones is still determined by the mechanism of internal regulation of short day animal's exposure to light changes. Shortening light may also help increase the reproductive activity of goat and thus increase productivity.

Behavioral Observations on Introduced Hu Sheep in Henan Province,China

Hu Sheep is a local sheep breed in the plain of Taihu, China. Due to the natural conditions in Taihu and human domestication, Hu Sheep is gradually featured with high adaptability, fast growth rate, early maturity and high productivity, which make them to be a unique and rare breed of sheep. In the present study, an experiment was conducted by means of instantaneous scan sampling, focal animal sampling and all-occurrence sampling to learn about Hu Sheep's behavior and activity pattern under certain feeding management and ecological condition. The result showed that the activity time budgets for several behaviors were different between rams and ewes, with respect to feeding (rams 30.60% vs. ewes 33.23%), ruminating (33.43% vs.35.30%); sleeping (19.92% vs. 13.69%), standing (4.13% vs. 5.26%), moving (8.10% vs. 7.46%), and other behaviors (3.86% vs.5.06%). A circadian activity rhythm was shown in some behaviors; e.g., total feeding time was greater in the daytime than at night, whereas resting time showed the opposite tendency. Moving mostly occurred in the daytime, and ruminating mainly occurred at night. Additionally, feeding activity occurred 32.22 times per day in rams and 31.73 times per day in ewes, whereas ruminating activity after feeding occurred 19.83 times per day in rams and 24.34 times per day in ewes. For each food bolus,the average ruminating time was 51.22 s in rams and 49.52 s in ewes, with 68.22 bouts of rumination per day in rams and57.35 bouts of rumination in ewes. By conducting the experiment, we studied and grasped the local Hu Sheep's main behavior and regularity which are of great significance on improving the feeding management and reducing diseases.